The following disclosure relates generally to multideck aircraft and, more particularly, to transonic aircraft having multipurpose lower decks for carrying passengers or passengers and cargo.
Conventional transport aircraft typically include a passenger cabin on an upper deck and a cargo hold on a lower deck. This configuration allows airlines to generate revenue by transporting both passengers and cargo over selected routes. On some routes, however, there is a greater demand for transporting passengers than cargo. On these routes, the airlines may accordingly prefer to use some of the space on the lower cargo deck for additional passenger seating.
One problem with adding passenger seating, sleeping cabins, or other passenger service facilities to lower decks is that lower decks typically provide insufficient standing height: One attempt to overcome this problem is disclosed in U.S. Pat. No. 5,752,673 to Schliwa et al (xe2x80x9cSchliwaxe2x80x9d). Schliwa discloses lowering the floor in an aisle section of the lower deck to provide at least enough clearance for a standing person of normal height.
Another problem with using lower cargo decks for passengers is providing sufficient structure beneath the lower decks to protect the passengers in the event of a crash landing. Regulations could require at least 30 inches of compressible structure beneath the lower deck if the lower deck is to be used to carry passengers. Lowering the floor of the lower deck as proposed by Schliwa compounds this problem because it further reduces the space beneath the lower deck.
One approach to meet the compressible structure requirement is disclosed in U.S. Pat. No. 5,542,626 to Beuck et al (xe2x80x9cBeuckxe2x80x9d). Beuck discloses an energy absorbing structural unit that is attached to the underside of an aircraft fuselage. The structural unit proposed by Beuck is an add-on feature of considerable size that extends downwardly and outwardly around the lower half of the fuselage cross-section to protect a lower passenger deck in the event of an impact. Because of its size and complexity, implementing the Beuck approach may add considerable cost, weight and aerodynamic drag to an aircraft.
Aspects of the invention are directed to aircraft, such as transonic aircraft, having multipurpose lower decks usable for transporting passengers, cargo, or passengers and cargo. In one aspect, an aircraft fuselage includes a first fuselage portion and a second fuselage portion positioned aft of the first fuselage portion. The first fuselage portion can have a first dimension at least approximately parallel to a yaw axis, and the second fuselage portion can have a second dimension at least approximately parallel to the yaw axis that is less than the first dimension. The aircraft fuselage can further include a first deck and a second deck. The first deck can extend at least within the first and second fuselage portions, and can have a first passenger portion configured to accommodate passengers. The second deck can extend at least within the first fuselage portion, and can have a second passenger portion configured to accommodate passengers. In another aspect, the second deck can further include a cargo portion configured to carry cargo containers.
In a further aspect of the invention, the aircraft fuselage can also include a third fuselage portion positioned aft of the second fuselage portion. The third fuselage portion can have a third dimension at least approximately parallel to the yaw axis that is greater than the second dimension. The first deck can extend within the third fuselage portion.
In still another aspect of the invention, a method for manufacturing an aircraft includes providing a first fuselage portion and attaching a second fuselage portion to the first fuselage portion aft of the first fuselage portion. The first fuselage portion can have a first dimension at least approximately parallel to a yaw axis, and the second fuselage portion can have a second dimension at least approximately parallel to the yaw axis that is less than the first dimension. The method can further include positioning a wing at least proximate to the second fuselage portion, extending at least generally outboard relative to the second fuselage portion. The method can additionally include positioning a first deck at least within the first and second fuselage portions, and positioning a second deck at least within the first fuselage portion. The first deck can include a first passenger portion configured to accommodate passengers, and the second deck can include a second passenger portion configured to accommodate passengers.